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  <h1>Source code for django.views.decorators.cache</h1><div class="highlight"><pre>
<span></span><span class="kn">from</span> <span class="nn">functools</span> <span class="k">import</span> <span class="n">wraps</span>

<span class="kn">from</span> <span class="nn">django.middleware.cache</span> <span class="k">import</span> <span class="n">CacheMiddleware</span>
<span class="kn">from</span> <span class="nn">django.utils.cache</span> <span class="k">import</span> <span class="n">add_never_cache_headers</span><span class="p">,</span> <span class="n">patch_cache_control</span>
<span class="kn">from</span> <span class="nn">django.utils.decorators</span> <span class="k">import</span> <span class="p">(</span>
    <span class="n">available_attrs</span><span class="p">,</span> <span class="n">decorator_from_middleware_with_args</span><span class="p">,</span>
<span class="p">)</span>


<span class="k">def</span> <span class="nf">cache_page</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Decorator for views that tries getting the page from the cache and</span>
<span class="sd">    populates the cache if the page isn&#39;t in the cache yet.</span>

<span class="sd">    The cache is keyed by the URL and some data from the headers.</span>
<span class="sd">    Additionally there is the key prefix that is used to distinguish different</span>
<span class="sd">    cache areas in a multi-site setup. You could use the</span>
<span class="sd">    get_current_site().domain, for example, as that is unique across a Django</span>
<span class="sd">    project.</span>

<span class="sd">    Additionally, all headers from the response&#39;s Vary header will be taken</span>
<span class="sd">    into account on caching -- just like the middleware does.</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="c1"># We also add some asserts to give better error messages in case people are</span>
    <span class="c1"># using other ways to call cache_page that no longer work.</span>
    <span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">args</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">1</span> <span class="ow">or</span> <span class="n">callable</span><span class="p">(</span><span class="n">args</span><span class="p">[</span><span class="mi">0</span><span class="p">]):</span>
        <span class="k">raise</span> <span class="ne">TypeError</span><span class="p">(</span><span class="s2">&quot;cache_page has a single mandatory positional argument: timeout&quot;</span><span class="p">)</span>
    <span class="n">cache_timeout</span> <span class="o">=</span> <span class="n">args</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span>
    <span class="n">cache_alias</span> <span class="o">=</span> <span class="n">kwargs</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s1">&#39;cache&#39;</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
    <span class="n">key_prefix</span> <span class="o">=</span> <span class="n">kwargs</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s1">&#39;key_prefix&#39;</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
    <span class="k">if</span> <span class="n">kwargs</span><span class="p">:</span>
        <span class="k">raise</span> <span class="ne">TypeError</span><span class="p">(</span><span class="s2">&quot;cache_page has two optional keyword arguments: cache and key_prefix&quot;</span><span class="p">)</span>

    <span class="k">return</span> <span class="n">decorator_from_middleware_with_args</span><span class="p">(</span><span class="n">CacheMiddleware</span><span class="p">)(</span>
        <span class="n">cache_timeout</span><span class="o">=</span><span class="n">cache_timeout</span><span class="p">,</span> <span class="n">cache_alias</span><span class="o">=</span><span class="n">cache_alias</span><span class="p">,</span> <span class="n">key_prefix</span><span class="o">=</span><span class="n">key_prefix</span>
    <span class="p">)</span>


<div class="viewcode-block" id="cache_control"><a class="viewcode-back" href="../../../../topics/http/decorators.html#django.views.decorators.cache.cache_control">[docs]</a><span class="k">def</span> <span class="nf">cache_control</span><span class="p">(</span><span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="k">def</span> <span class="nf">_cache_controller</span><span class="p">(</span><span class="n">viewfunc</span><span class="p">):</span>
        <span class="nd">@wraps</span><span class="p">(</span><span class="n">viewfunc</span><span class="p">,</span> <span class="n">assigned</span><span class="o">=</span><span class="n">available_attrs</span><span class="p">(</span><span class="n">viewfunc</span><span class="p">))</span>
        <span class="k">def</span> <span class="nf">_cache_controlled</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kw</span><span class="p">):</span>
            <span class="n">response</span> <span class="o">=</span> <span class="n">viewfunc</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kw</span><span class="p">)</span>
            <span class="n">patch_cache_control</span><span class="p">(</span><span class="n">response</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
            <span class="k">return</span> <span class="n">response</span>
        <span class="k">return</span> <span class="n">_cache_controlled</span>
    <span class="k">return</span> <span class="n">_cache_controller</span></div>


<div class="viewcode-block" id="never_cache"><a class="viewcode-back" href="../../../../topics/http/decorators.html#django.views.decorators.cache.never_cache">[docs]</a><span class="k">def</span> <span class="nf">never_cache</span><span class="p">(</span><span class="n">view_func</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Decorator that adds headers to a response so that it will</span>
<span class="sd">    never be cached.</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="nd">@wraps</span><span class="p">(</span><span class="n">view_func</span><span class="p">,</span> <span class="n">assigned</span><span class="o">=</span><span class="n">available_attrs</span><span class="p">(</span><span class="n">view_func</span><span class="p">))</span>
    <span class="k">def</span> <span class="nf">_wrapped_view_func</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
        <span class="n">response</span> <span class="o">=</span> <span class="n">view_func</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
        <span class="n">add_never_cache_headers</span><span class="p">(</span><span class="n">response</span><span class="p">)</span>
        <span class="k">return</span> <span class="n">response</span>
    <span class="k">return</span> <span class="n">_wrapped_view_func</span></div>
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